//字符串
main() {
  var s1 = 'Single quotes work well for string literals.';
  var s2 = "Double quotes work just as well.";
  var s3 = 'It\'s easy to escape the string delimiter.';
  var s4 = "It's even easier to use the other delimiter.";

  var s = 'string interpolation';
  assert('Dart has $s, which is very handy.' ==
      'Dart has string interpolation, ' + 'which is very handy.');
  assert('That deserves all caps. ' + '${s.toUpperCase()} is very handy!' ==
      'That deserves all caps. ' + 'STRING INTERPOLATION is very handy!');

  var s5 = 'String '
      'concatenation'
      " works even over line breaks.";
  assert(s5 ==
      'String concatenation works even over '
      'line breaks.');

  var s6 = 'The + operator ' + 'works, as well.';
  assert(s6 == 'The + operator works, as well.');

  var s7 = '''
You can create
multi-line strings like this one.
''';

  var s8 = """
This is also a
multi-line string.
""";

  print('1.' + s1);
  print('2.' + s2);
  print('3.' + s3);
  print('4.' + s4);
  print('5.' + s5);
  print('6.' + s6);
  print('7.' + s7);
  print('8.' + s8);
}
//EOP
